Force useCapture for mouseenter/mouseleave?

Right now it's not possible to listen to mouseenter/mouseleave in the bubble phase:
http://jsfiddle.net/lazd/3s488q3o/2/

Currently, you must explicitly listen in the capture phase for mouseenter/mouseleave events (event with native `addEventListener`, as show in the fiddle).

Given that these events do not bubble, the only way to delegate to them is to use the capture phase. Should we do that by default, as we do for focus and blur?

### Version

1.0.0